The present invention relates to methods and apparatus for printing a graphic product on sheet material in accordance with a printing program and stored data representative of the graphic product, and more particularly to methods and apparatus for printing a wide format multicolor graphic product on a printing sheet, such as a vinyl sheet for use as signage.
Known in the art are thermal printing apparatus for generating signs, designs, characters and other graphic products on a printing sheet in accordance with a printing program and data representative of the graphic product. Typically, a thermal printer interposes a donor sheet that includes donor material and a backing between a thermal printhead and the printing sheet. The thermal printhead includes an array of thermal printing elements. The thermal printhead prints by pressing the donor sheet against the printing sheet and selectively energizing the thermal printing elements of the array, thereby selectively transferring pixels of donor medium from the donor sheet to the printing sheet. Movement of the printing sheet relative to the thermal printhead (or vice versa) while pressing the donor sheet against the printing sheet with the thermal printhead draws fresh donor sheet past the thermal printhead. The printing sheet typically includes a vinyl layer secured to a backing layer by a pressure sensitive adhesive so that after printing the vinyl bearing the graphic product can be cut and stripped from the backing material and affixed to an appropriate sign board or other material for display.
The proper printing of many graphic products, such as commercial artwork or signage, can require high quality print work. Often, it is desired that the final multicolor graphic product be physically large, such as several feet wide by tens of feet long. Typically, existing thermal printers are limited in the width of printing sheet that they can print upon. For example, one popular thermal printer prints on sheets that are one foot wide. Accordingly, the final graphic product is often assembled from separately printed strips of printing sheet that must be secured to the signboard in proper registration with one another. Often, the registration is less than perfect and the quality of the final graphic product suffers, especially when backlit.
Wide format thermal printers are known in the art. For example, one wide format thermal printer currently available can accommodate a printing sheet up to three feet wide and uses four full width (i.e., three feet wide) printheads, each interposing a different color donor sheet between the printhead and the printing sheet. Accordingly, far fewer seams, if any at all, require alignment when creating the sign or other product. Also, the use of four printheads allows faster printing of the multicolor graphic product.
Unfortunately, this type of machine can be expensive to manufacture and to operate. For example, each printhead, at a typical resolution of 300 dpi, includes literally thousands of thermal printing elements, all of which are typically required to have resistances that are within a narrow tolerance range. Such a thermal printhead is difficult and expensive to manufacture, and moreover, burnout of simply a few thermal printing elements can require replacement of the entire printhead. Furthermore, donor sheet is also expensive, and the full-width printing heads can be wasteful of donor sheet when printing certain types of, or certain sections of, graphic products. For example, consider that a single color stripe one inch wide and perhaps a foot long is to be printed in center of the printing sheet. Though the printed object occupies {fraction (1/12)} of a square foot, an area of donor sheet that is three feet wide by one foot long, or three square feet, is transferred past the print head when printing the above object, and hence consumed. The printing of a wide format graphic product that includes a narrow border about the periphery of the printing sheet is another example that typically can be wasteful of donor sheet when printing with the above wide format thermal printer.
Other wide format printers are known in the art, such as wide format ink-jet printers, which can also print in a single pass. However, inkjet printed multicolor graphic products are typically not stable when exposed to the elements (e.g., wind, sun, rain) or require special post-printing treatment to enhance their stability, adding to the cost and complexity of printing with such apparatus.
Accordingly, it is an object of the present invention to address one or more of the foregoing and other deficiencies and disadvantages of the prior art.
Other objects will in part appear hereinafter and in part be apparent to one of ordinary skill in light of the following disclosure, including the claims.
In one aspect, the invention provides a method of thermally printing a color plane of a multicolor graphic product on a printing sheet responsive to machine readable data representative of the graphic product. The method includes the following steps:
selecting a donor sheet corresponding to the color plane to be printed and interposing the donor sheet between a thermal printhead and the printing sheet, the thermal printhead having an array of printing elements extending for a printing width along a printing sheet translation axis;
printing the color plane onto the printing sheet in successive print swaths by translating the thermal printhead along a print axis orthogonal to the printing sheet translation axis and selectively energizing the thermal printing elements while pressing the donor sheet against the printing sheet with the thermal printhead;
translating the printing sheet in the direction of the printing sheet translation axis between print swaths; and
wherein, for at least one print swath, when consecutive pixels to be printed are separated by more than a minimum distance in the direction of the print axis, printing that swath includes refraining from pressing the donor sheet against the printing sheet with the printhead when translating the printhead at least part of the distance between the consecutive pixels, whereby the refraining from pressing substantially prevents donor sheet from being drawn past the printhead, thereby conserving donor sheet.
In another aspect, the invention provides a method of printing with a thermal printer that prints a multicolor graphic product on a printing sheet in each of different color planes responsive to selected machine readable data representative of the graphic product. The method includes the following steps:
A) selecting a supply length of donor sheet corresponding to the color plane to be printed and interposing a section of the supply length between the thermal printhead and the printing sheet, the thermal printhead having an array of printing elements extending along a printing sheet translation axis;
B) printing the color plane on the printing sheet in print swaths extending along a print axis substantially orthogonal to printing sheet translation axis by repeating the following steps 1) and 2) alternately
1) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet with the thermal printhead so as to draw the donor sheet past the printhead;
2) translating the printing sheet in the direction of the printing sheet translation axis between print swaths; and
C) performing steps A) and B) for each of the color planes to be printed to print the multicolor graphic product on the printing sheet, wherein when printing at least one of the color planes the printing sheet is translated in the opposite direction along the printing sheet translation axis between successive print swaths to that in which it is translated between successive swaths when printing a different color plane; and
wherein, for at least one print swath, when consecutive pixels to be printed are separated by more than a minimum distance in the direction of the print axis, printing that swath includes refraining from pressing the donor sheet against the printing sheet with the printhead when translating the printhead at least part of the distance between the consecutive pixels, whereby the refraining from pressing substantially prevents donor sheet from being drawn past the printhead, thereby conserving donor sheet.
In an additional aspect, the invention provides a method of printing with a thermal printer that prints a multicolor graphic product on a printing sheet in separate color planes responsive to machine readable data representative multicolor graphic product. The method includes the following steps:
A) selecting a supply length of donor sheet corresponding to a color plane to be printed and interposing a section of the supply length between a thermal printhead and the printing sheet, the thermal printhead having an array of printing elements extending from a trailing end to a leading end along a printing sheet translation axis;
B) printing the color plane on the printing sheet in print swaths extending along a print axis substantially orthogonal to the printing sheet translation axis by repeating the following steps 1) and 2) alternately
1) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet with the thermal printhead so as to draw the donor sheet past the printhead and print on the printing sheet;
2) translating the printing sheet in the direction of the printing sheet translation axis in an integer number of separate steps, each step translating the printing sheet by a translation increment substantially equal to the printing width; and
C) wherein in performing step B), at least one of the steps 1) includes translating the printing sheet in at least two steps, wherein one of the steps translates the printing sheet by a distance less than the increment and the other and any additional steps each translate the printing sheet by the increment.
In yet a further aspect, the invention provides a method of printing with a thermal printer that prints a multicolor graphic product on a printing sheet in separate color planes responsive to machine readable data representative multicolor graphic product. The method includes the following steps:
A) organizing a selected color plane into selected areas of the color plane, wherein within each area the objects to be printed are within a selected distance of each other along a printing sheet translation axis and wherein the objects within any one area are separated in the direction of the printing sheet translation axis from the objects in the other areas by a distance greater than the selected distance;
B) selecting a supply length of donor sheet corresponding to the color plane to be printed and interposing a section of the supply length between the thermal printhead and the printing sheet;
C) printing each of the areas of the color plane on the printing sheet in print swaths having a printing width and extending along a print axis orthogonal to the printing sheet translation axis by repeating the steps 1) and 2) alternately
1) a) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet so as to draw the donor sheet past the printhead; and
b) translating the printing sheet by a selected increment in the direction of the printing sheet translation axis between successive print swaths having a swath width in the direction of the printing sheet translation axis, and alternately repeating steps a) and b) as necessary until the area is printed; and
2) before printing the next area translating the printing sheet in the direction of the printing sheet translation axis by the distance substantially equal to the distance separating the area printed in 1) above and the next area to be printed.
In a further aspect, the invention provides a method of printing with a thermal printer that prints a multicolor graphic product on a printing sheet in each of different color planes responsive to machine readable data representative of the graphic product. The method includes the steps of:
A) selecting a supply length of donor sheet corresponding to the color plane to be printed and interposing a section of the supply length between the thermal printhead and the printing sheet;
B) printing the color plane on the printing sheet in print swaths extending along a print axis, and having a selected width along a printing sheet translation axis substantially orthogonal to the print axis, by repeating the steps 1) and 2) alternately
1) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet so as to draw the donor material past the printhead;
2) translating the printing sheet in the direction of the printing sheet translation axis by a distance substantially equal to at least the selected width; and
C) performing steps A) and B) for each of the color planes to be printed to print the multicolor graphic product on the printing sheet, wherein when printing at least one of the color planes the printing sheet is translated between successive swaths in the opposite direction along the printing sheet translation axis to that in which it is translated when printing successive swath of a different color plane; and
wherein performing one of the steps 1) for at least one of the color planes includes translating the printing sheet in at least two steps wherein one of the steps translates the printing sheet a distance less than the selected width and any additional steps are each substantially equal to the selected width.
The invention can also include a method of thermally printing a color plane of a multicolor graphic product on a printing sheet responsive to machine readable data representative of the color plane, where the method includes the following steps:
A) selecting a donor sheet corresponding to the color plane to be printed and interposing the donor sheet between a thermal printhead having an array of printing elements extending for a predetermined printing width along a printing sheet translation axis;
B) selecting first and second portions of the color plane to be printed on the printing sheet, the step of selecting including
determining the end in the direction of the printing sheet translation axis of the color plane to which the printhead is currently the nearest; and
selecting the first portion of the color plane to be between the printhead and the nearer end of the color plane and the second portion to be the remainder of the color plane; and
C) printing the first portion of the color plane onto the printing sheet before printing the second portion of the color plane, wherein printing each of the portions includes printing in successive print swaths, each having a printing width, by translating the thermal printhead along a print axis orthogonal to the printing sheet translation axis and translating the printing sheet in the direction of the printing sheet translation axis between print swaths.
In a further additional aspect, the invention provides a method of thermally printing a color plane of a multicolor graphic product on a printing sheet responsive to machine readable data representative of the color plane, where the method includes the following steps:
A) selecting a donor sheet corresponding to the color plane to be printed and interposing the donor sheet between a thermal printhead having an array printing elements extending for a predetermined printing width along a printing sheet translation axis;
B) printing first and second portions of the color plane, wherein printing each of the portions includes printing in successive prints swaths having a printing width in the direction of the printing sheet translation axis by successively translating the thermal printhead along a print axis orthogonal to the printing sheet translation axis and translating the printing sheet in the direction of the printing sheet translation axis between print swaths; and
wherein when printing the first portion of the color plane the printing sheet is translated in one direction along the printing sheet translation axis between print swaths and when printing the second portion the printing sheet is translated in the opposite direction between print swaths.
In another aspect, the invention provides a method of printing with a thermal printer that prints a multicolor graphic product on a printing sheet in each of different color planes responsive to machine readable data representative of the multicolor graphic product, where the method includes the following steps:
A) selecting a supply length of donor sheet corresponding to the color plane to be printed and interposing a section of the supply length between the thermal printhead and the printing sheet;
B) printing the color plane on the printing sheet in print swaths extending along a print axis and having a selected width along a printing sheet translation axis substantially orthogonal to the print axis by repeating the following steps 1) and 2) alternately
1) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet so as to print on the printing sheet and draw the donor sheet past the printhead;
2) translating the printing sheet a distance substantially equal to at least the selected width in a selected direction along the printing sheet translation axis; and
C) performing steps A) and B) for each of the remaining color planes to be printed to print the multicolor graphic product on the printing sheet; and
wherein after finishing printing a color plane and prior to printing the next color plane, performing the step of:
determining whether one of the end of the color plane to be printed next is nearer, in the direction of the printing sheet translation axis, the current position of the printhead than the other end of the color plane to be printed; and
when one end is nearer, printing at least part of that portion of the color plane between the printhead and the nearer end of the color plane before printing a least part of portion of the color plane between the printhead and the other end of the color plane.
The invention can also include another method of thermally printing a color plane of a multicolor graphic product on a printing sheet responsive to machine readable data representative of the color plane, where the method includes the following steps:
determining that the color plane to be printed includes an object to be knocked out by one of another spot color object and a process color object in the finished graphic product to be printed on the printing sheet;
A) selecting a donor sheet corresponding to the color plane to be printed and interposing the donor sheet between a thermal printhead having an array of printing elements extending along a printing sheet translation axis;
B) printing the color plane onto the printing sheet including printing in successive prints swaths, each having a printing width, by translating the thermal printhead along a print axis orthogonal to the printing sheet translation axis and selectively energizing the thermal printing elements responsive to the machine readable data and, between printing successive print swaths, translating the printing sheet in the direction of the printing sheet translation axis, and
refraining from printing those areas of the color plane determined to be knocked out.
In another aspect, the invention includes a method for processing data representative of a multicolor graphic product with a computer for printing the multicolor graphic product on a printing sheet in separate color planes with a thermal printer that translates the printing sheet along a printing sheet translation axis and translates a thermal printhead along a print axis perpendicular to the printing sheet translation axis, and wherein the thermal printhead includes an array of thermal printing elements extending along the direction of the printing sheet translation axis for printing in print swaths extending in the direction of the print axis. The method includes the following steps:
providing a machine readable data file including data representative of the multicolor graphic product
selecting a color plane to be printed;
examining the data file to select objects that are of the color of the selected color plane;
associating a rectangular area of the color plane with each object;
combining those areas that are within a selected distance of each other along printing sheet translation axis;
increasing the dimension, of each of the areas, that extends in the direction of the print axis such that the width is an integral number of printing widths;
selecting each of the areas for printing, and when selecting each of the areas, performing the steps of:
dividing the selected area into an integral number of print swaths;
selecting each of the print swaths in turn and storing machine readable data corresponding to the objects to be printed in the selected print swath for instructing the printer for printing the print swath.
According to the invention there is also provided wide format thermal printer apparatus. In one aspect, the invention provides a wide format thermal printer for printing a multicolor graphic product onto a printing sheet in separate color planes and responsive to machine readable data representative of the graphic product. The wide format thermal printer includes:
a workbed including a platen and providing a worksurface for supporting the printing sheet, the worksurface containing a print axis and printing sheet translation axis perpendicular to the print axis;
printing sheet translation means for translating the printing sheet in the direction of the printing sheet translation axis;
a thermal printhead translatable in the direction of the print axis, the thermal printhead including an array of thermal printing elements extending substantially parallel to the printing sheet translation axis, the thermal printer including a first actuator for translating the thermal printhead in the direction of the print axis and a second actuator coupled to the printhead for lifting the printhead away from the printing sheet for refraining from pressing the donor sheet against the printing sheet such that donor sheet is not drawn past the printhead when the thermal printhead is translated in the direction of the print axis;
donor sheet apparatus including a take-up shaft coupled to a take-up motor and a supply shaft, the take-up and supply shafts for coupling to take-up rolls and supply rolls, respectively, of donor sheet, the take-up motor for winding the donor sheet on the take-up roll after the donor sheet is drawn from the supply roll and interposed between the thermal printhead and the printing sheet, the donor sheet apparatus being translatable with the thermal printhead in the direction of the print axis;
means for securing the printing sheet to the workbed when printing on the printing sheet and releasing the printing sheet from the workbed when translating the printing sheet;
a controller in communication with, and for controlling, the printing sheet translation means, the thermal printhead, the take-up motor, the first and second actuators and the means for securing the printing sheet, and wherein the controller includes programming stored in a memory associated therewith for:
1) printing a color plane onto the printing sheet in successive print swaths by translating the thermal printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the donor sheet against the printing sheet with the thermal printhead;
2) translating the printing sheet in the direction of the printing sheet translation axis between the printing of successive print swaths; and for
3) when printing at least one print swath, determining when consecutive pixels to be printed are separated by more than a minimum distance in the direction of the print axis, and upon determining that the consecutive pixel are so separated, lifting the thermal printhead away from the printing sheet when translating the printhead at least part of the distance between the consecutive pixels for substantially preventing donor sheet from being drawn past the printhead, thereby conserving donor sheet.
In another aspect, the invention provides a wide format thermal printer for printing a multicolor graphic product onto a printing sheet in separate color planes and responsive to machine readable data representative of the graphic product where the wide format thermal printer includes the following:
a workbed including a platen and providing a worksurface for supporting the printing sheet, the worksurface containing a print axis and printing sheet translation axis perpendicular to the print axis;
printing sheet translation means for translating the printing sheet along a printing sheet translation axis;
a thermal printhead translatable in the direction of the print axis, the thermal printhead including an array of thermal printing elements extending parallel to the printing sheet translation axis, the thermal printer including a first actuator for translating the thermal printhead in the direction of the print axis and a second actuator coupled to the printhead for lifting the printhead away from the printing sheet for refraining from pressing the donor sheet against the printing sheet such that donor sheet is not drawn past the printhead the thermal printhead is translated in the direction of the print axis;
donor sheet apparatus including a take-up shaft coupled to a take up motor and a supply shaft, the take-up and supply shafts for coupling to take-up rolls and supply rolls, respectively, of donor sheet, the take-up motor for winding the donor sheet on the take-up roll after the donor sheet is drawn from the supply roll and interposed between the thermal printhead and the printing sheet, the donor sheet apparatus being translatable with the thermal printhead in the direction of the print axis;
means for securing the printing sheet to the workbed when printing on the printing sheet and releasing the printing sheet from the workbed when translating the printing sheet;
a controller in communication with, and for controlling, the printing sheet translation means, the thermal printhead, the take-up motor, the first and second actuators and the means for securing the printing sheet, and wherein the controller includes programming stored in a memory associated therewith for
A) printing the color plane on the printing sheet in print swaths extending along a print axis substantially orthogonal to the printing sheet translation axis by repeating the following items 1) and 2) alternately
1) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet with the thermal printhead so as to draw the donor sheet past the printhead and print on the printing sheet in print swaths extending in the direction of the print axis and having a swath width in the direction of the printing sheet translation axis;
2) translating the printing sheet in the direction of the printing sheet translation axis in an integer number of separate steps, each step translating the printing sheet by a translation increment substantially equal to the printing width; and
B) wherein 1) includes translating the printing sheet in at least two steps, wherein one of the steps translates the printing sheet by a distance less than the translation increment and the other and any additional steps each translate the printing sheet by the translation increment.
In an additional aspect, the invention provides a wide format thermal printer for printing a multicolor graphic product onto a printing sheet in separate color planes and responsive to machine readable data representative of the graphic product. The wide format thermal printer includes the following:
a workbed including a platen and providing a worksurface for supporting the printing sheet, the worksurface containing a print axis and printing sheet translation axis perpendicular to the print axis;
printing sheet translation means for translating the printing sheet along a printing sheet translation axis;
a thermal printhead translatable in the direction of the print axis, the thermal printhead including an array of thermal printing elements extending parallel to the printing sheet translation axis, the thermal printer including a first actuator for translating the thermal printhead in the direction of the print axis and a second actuator coupled to the printhead for lifting the printhead away from the printing sheet for refraining from pressing the donor sheet against the printing sheet such that donor sheet is not drawn past the printhead the thermal printhead is translated in the direction of the print axis;
donor sheet apparatus including a take-up shaft coupled to a take-up motor and a supply shaft, the take-up and supply shafts for coupling to take-up rolls and supply rolls, respectively, of donor sheet, the take-up motor for winding the donor sheet on the take-up roll after the donor sheet is drawn from the supply roll and interposed between the thermal printhead and the printing sheet, the donor sheet apparatus being translatable with the thermal printhead in the direction of the print axis;
means for securing the printing sheet to the workbed when printing on the printing sheet and releasing the printing sheet from the workbed when translating the printing sheet;
a controller in communication with, and for controlling, the printing sheet translation means, the thermal printhead, the take-up motor, the first and second actuators and the means for securing the printing sheet, and wherein the controller includes programming stored in a memory associated therewith for
A) organizing a selected color plane into selected areas of the color plane, wherein within each area the objects to be printed are within a selected distance of each other along a printing sheet translation axis and wherein the objects within any one area are separated in the direction of the printing sheet translation axis from the objects in the other areas by a distance greater than the selected distance;
B) printing each of the areas of the color plane on the printing sheet in print swaths extending along a print axis orthogonal to the printing sheet translation axis and having a swath width in the direction of the printing sheet translation axis by repeating the steps 1) and 2) alternately
1) a) translating the printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the selected donor sheet against the printing sheet so as to draw the donor sheet past the printhead; and before printing the next area
xe2x80x83b) translating the printing sheet in the direction of the printing sheet translation axis, by a selected increment substantially equal to the swath width, between successive print swaths, and alternately repeating steps a) and b) as necessary until the area is printed; and
2) translating the printing sheet in the direction of the printing sheet translation axis by the distance substantially equal to the distance separating the area printed in 1) above and the next area to be printed.
In yet a further aspect, the invention provides a wide format thermal printer for printing a multicolor graphic product onto a printing sheet in separate color planes and responsive to machine readable data representative of the graphic product, where the wide format thermal printer includes:
a workbed including a platen and providing a worksurface for supporting the printing sheet, the worksurface containing a print axis and printing sheet translation axis perpendicular to the print axis;
printing sheet translation means for translating the printing sheet along a printing sheet translation axis;
a thermal printhead translatable in the direction of the print axis, the thermal printhead including an array of thermal printing elements extending parallel to the printing sheet translation axis, the thermal printer including a first actuator for translating the thermal printhead in the direction of the print axis;
donor sheet apparatus including a take-up shaft coupled to a take-up motor and a supply shaft, the take-up and supply shafts for coupling to take-up rolls and supply rolls, respectively, of donor sheet, the take-up motor for winding the donor sheet on the take-up roll after the donor sheet is drawn from the supply roll and interposed between the thermal printhead and the printing sheet, the donor sheet apparatus being translatable with the thermal printhead in the direction of the print axis;
means for securing the printing sheet to the workbed when printing on the printing sheet and releasing the printing sheet from the workbed when translating the printing sheet;
a controller in communication with, and for controlling, the printing sheet translation means, the thermal printhead, the take-up motor, the first and second actuators and the means for securing the printing sheet, and wherein the controller includes programming stored in a memory associated therewith for:
A) selecting first and second portions of the color plane to be printed on the printing sheet, the selecting including
determining the end in the direction of the printing sheet translation axis of the color plane to which the printhead is currently the nearest; and
selecting the first portion of the color plane to be between the printhead and the nearer end of the color plane and the second portion to be the remainder of the color plane; and
B) printing the first portion of the color plane onto the printing sheet before printing the second portion of the color plane, wherein printing each of the portions includes printing in successive print swaths, each having a printing width, by translating the thermal printhead along a print axis orthogonal to the printing sheet translation axis and selectively energizing the thermal printing elements responsive to the machine readable data representative of the multicolor graphic product and translating the printing sheet in the direction of the printing sheet translation axis between print swaths.
In another aspect, there is provided according to the invention a wide format thermal printer for printing a multicolor graphic product onto a printing sheet in separate color planes and responsive to machine readable data representative of the graphic product, where the wide format thermal printer includes:
a workbed including a platen and providing a worksurface for supporting the printing sheet, the worksurface containing a print axis and printing sheet translation axis perpendicular to the print axis;
printing sheet translation means for translating the printing sheet along a printing sheet translation axis;
a thermal printhead translatable in the direction of the print axis, the thermal printhead including an array of thermal printing elements extending parallel to the printing sheet translation axis, the thermal printer including a first actuator for translating the thermal printhead in the direction of the print axis and a second actuator coupled to the printhead for lifting the printhead away from the printing sheet for refraining from pressing the donor sheet against the printing sheet such that donor sheet is not drawn past the printhead the thermal printhead is translated in the direction of the print axis;
donor sheet apparatus including a take-up shaft coupled to a take up motor and a supply shaft, the take-up and supply shafts for coupling to take-up rolls and supply rolls, respectively, of donor sheet, the take-up motor for winding the donor sheet on the take-up roll after the donor sheet is drawn from the supply roll and interposed between the thermal printhead and the printing sheet, the donor sheet apparatus being translatable with the thermal printhead in the direction of the print axis
means for securing the printing sheet to the workbed when printing on the printing sheet and releasing the printing sheet from the workbed when translating the printing sheet;
a controller in communication with, and for controlling, the printing sheet translation means, the thermal printhead, the take-up motor, the first and second actuators and the means for securing the printing sheet, and wherein the controller includes programming stored in a memory associated therewith for:
1) determining from the machine readable data that a first color plane to be printed before a second color plane includes at least one object including a portion to be knocked out by an object of the color of the second color plane;
2) printing the first a color plane onto the printing sheet in successive print swaths, each having a printing width, by translating the thermal printhead in the direction of the print axis and selectively energizing the thermal printing elements while pressing the donor sheet against the printing sheet with the thermal printhead and, between successive print swaths, translating the printing sheet in the direction of the printing sheet translation axis between print swaths; and
3) refraining from printing that portion of the object determined to be knocked out.